(SciShow Kids intro)

Jessi: I love Summer! Days are long, we can eat lots of delicious frozen treats, and it's when I get to go outside on warm evenings and look for fireflies. If there are fireflies where you live, you've probably wondered how they make that bright yellowish glow, and why they light up in the first place. I know that I have. So let's see if we can shed a little light on what we know about these super cool animals.

Fireflies go by a couple of different names. In the United States, where they're mostly found in the East, some people call them lightning bugs, and in Europe they might be called glow worms, but none of these names are very accurate, because fireflies aren't flies, bugs, or even worms. They're actually beetles. This means they're related to animals like ladybugs and Japanese beetles. And like many beetles, fireflies go through metamorphosis. Metamorphosis is the series of changes that take place over a certain animal's life cycle.

Fireflies begin as eggs. Female fireflies lay their eggs underground, where they hatch and become larvae, and both an egg and a larva of a firefly can glow, just like an adult. After about a year, the larvae move into the next stage of metamorphosis, called the pupa stage. This is where the insects gradually change from looking like long, lumpy larvae into the adults that we recognize.

After they reach adulthood, fireflies only live for about a month or two. this is just long enough for them to reproduce, lay eggs, and start the life cycle all over again. And what fireflies eat depends on what part of the life cycle they're in. Larvae, since they live underground, eat things like snails and slugs, while adult fireflies eat pollen and nectar from flowers-- or, sometimes, other fireflies. Still, other adult fireflies seem to eat nothing at all. Some scientists think this might be because they live for such a short time.

And since fireflies and other beetles are insects, you know what that means. It means fireflies have what all insects have in common. They have six legs, and they have three main body parts: the head, the thorax, and the abdomen. And it's what goes on beneath the fireflies abdomen that makes it different from most other insects.

Fireflies have a special body part beneath their abdomens that does one thing: it makes light. When oxygen from the air enters this part of the body, it mixes with special chemicals inside, causing the firefly to glow. Scientists call this glow bioluminescence: light that comes from a living thing. Scientists know how bioluminescence works in fireflies, but they're not quite sure how the insects are able to turn it on and off in a specific pattern. That's a question that they're still studying.

But scientists do know a lot about why fireflies flash. First, flashing probably sends a warning to predators, just like some flashing lights send warnings to people. A firefly's light sends a message to hungry animals that their glowing bodies taste bad, so they should stay away. Flashing is also a way that fireflies communicate with each other. The blinking pattern might tell other fireflies not to get too close to their homes, or it might help fireflies that are of the same kind or species to identify each other. And sometimes the flashing might be a signal that one firefly sends to another to attract a mate. In many kinds of fireflies, the female can't fly. Instead, she'll cling to a leaf or a branch, flashing her light when she sees a male fly by.

And you know what else? Fireflies are really fun to catch! If you decide to catch them, make your yard and house as dark as possible. Not only will you be able to see the fireflies' lights more clearly, but darkness will also make the insects flash more frequently. If you use a flashlight, keep it pointed to the ground so you don't scare the fireflies away, and as you're catching fireflies, be gentle. Like all insects, fireflies are really delicate.

And even though some people might be tempted to keep them in a jar, you really shouldn't. If you catch one, it's best to just take the time to get a close look at it, admire it, and then let it go. Because remember, they don't live for very long. Summer is their time to shine.

So happy firefly season! And enjoy your Summer. And thanks for joining us on SciShow Kids. If you have a question, or just something you'd like to learn more about, let us know by leaving a comment below or emailing us at kids@thescishow.com see you later!